Processes for the preparation of olefins are known in the art.
US2003/0181777 describes a process wherein a conventional stream cracker C4-Raffinate-2, containing isobutane, 1-butene, n-butane, trans-2-butene and cis-2-butene, is contacted with a MTT type zeolite in the presence of a co-feed of methanol.
The process of US2003/0181777 requires a continuous stream of olefins, as without olefins the therein described cracking process can not be carried out. That is, variations in the amount of olefins fed, will have a large influence on the process.
At many refinery sites small waste streams containing C4 and C5 olefins are generated. Presently such olefins are blended into product fractions, converted into fuel components or sometimes even hydrogenated and used as fuel.
It would be desirable to be able to convert such “waste” olefins into valuable ethylene and propylene. Unfortunately such waste streams may not always be present as a continuous stream. The amounts in which such waste streams can be provided may vary widely in time and location. Processes such as those described in US2003/0181777, however, require a continuous feed stream.
It would therefore be desirable to have a process which allows one to process “waste” olefins, even if such “waste” olefins are provided as non-continuous stream.